R – Ist it a good idea to use NSUserDefaults to store the latest state of an iPhone application

cocoa-touchiphonensuserdefaultsuikit

I have an view-based application where the user can do a lot of customization things, like selecting colors, selecting pictures, and so on.

First, I thought about using sqlite3 for that, but since this would result in a table with only one row (no multi-user app), it seems like a big overhead to me. Then I heard about NSUserDefaults. But I am not sure where this data is stored. Is it stored in the app's sandbox? Or is it stored somewhere else? Do other apps have access to that data? Is it good for remembering this kind of customization stuff?

Best Answer

The NSUserDefaults class is meant for storing user preferences for your application. It's stored in a plist file in the application's sandbox Library directory.

[[NSUserDefaults standardUserDefaults] setObject:@"Test" forKey:@"myPref"];
NSString *val = [[NSUserDefaults standardUserDefaults] stringforKey:@"myPref"];

Related Solutions

R – NSUserDefaults: What’s the +resetStandardUserDefaults method good for? How to provide “system settings”

Yes, but it's a little different than what you're doing. NSUserDefaults has the registerDefaults method, which lets you populate the "blank" defaults from an NSDictionary with values you provide. Put this in the +initialize method in your app controller, and you'll know the default values are sensible. If the user defaults object finds a "real" value for a key, either one you set during the current application launch or loaded from disk, it will always take precedent over what you provided in registerDefaults. resetStandardUserDefaults will remove the shared user defaults object from memory and undo any customization you've made to it, it's not something you'll need to provide default values.

Also, keep in mind you can't just cast an object to a primitive NSInteger value as you're doing, you'll just end up with a number representing the memory location of the object's pointer. Either use NSUserDefault's integerForKey: to get a primitive directly, or use objectForKey: to get an NSNumber and use integerValue to get the primitive value.

Ios – How to reset the NSUserDefaults data in the iPhone simulator

You want NSUserDefaults removePersistentDomainForName. This will remove all user defaults for the application:

NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
[[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

For more information on the NSUserDefaults class see the Apple docs.

Alternately, if all you are concerned with is data in the iOS Simulator, you can do that via iOS Simulator > Reset Content and Settings.

enter image description here

Best Answer

Related Solutions

R – NSUserDefaults: What’s the +resetStandardUserDefaults method good for? How to provide “system settings”

Ios – How to reset the NSUserDefaults data in the iPhone simulator

Related Topic